1. Field of the Invention
Embodiments of the invention relate to an electromedical implant configured to improve arrhythmia detections based on active muscle noise detection, specifically and not by way of limitation, embodiments improve the specificity of the arrhythmia detection by active detection of lead or device movement that induces signal artifacts. The electromedical implant can, for example, be an appropriately configured implantable loop recorder or ILR for long terming monitoring of electrocardiograms or ECGs or other implantable pacemaker or an implantable cardioverter/defibrillator or ICD, or any combination thereof.
2. Description of the Related Art
Arrhythmia detections based on the QRS detection of the subcutaneous ECG or sECG in implantable loop recorders or ILRs are often disturbed by external noise, specifically muscle noise that is generated by a patient, for example due to the movement of the shoulder area of the patient. This noise is can be classified falsely as arrhythmia which for example triggers sECG recordings or alarms to the physician. Existing implantable monitoring systems, such as ILRs have a very low specificity, i.e., high number of false positives, when it comes to arrhythmia detections such as high ventricular rate or atrial fibrillation. Recent studies reported an overall specificity of ILRs of about 15%, with a worst-case specificity for the detection of high ventricular rates of 0.3%. Several reasons have been identified, starting from very small subcutaneous ECG signals to the induction of noise generated by moving artifacts. Existing solutions are very limited and generally attempt to suspend arrhythmia detection in case of high amplitude/high frequency noise. Although such approaches may slightly improve the overall specificity, the problem of “rhythmic noise” artifacts occurring approximately every second to ˜5×/second cannot be identified and filtered out using known techniques, for example that are unable to identify this type of noise. “Rhythmic noise” is typically generated in muscle surrounding the ILR, which is related to arm and shoulder movements of the patient (e.g. climbing up stairs, walking/running, or brushing teeth).